Immobilization of Brønsted basic hexaniobate on the Lewis acidic zirconia using an emulsion assisted self-assembly strategy for synergistic boosting of nerve agent simulant decontamination

Abstract

The hydrolytic decontamination of organophosphorus nerve agents can be promoted using Brønsted bases or Lewis acids, but the fabrication of catalytic materials with both Lewis acidic centers and Brønsted base sites is a great challenge due to their essential incompatibility. Herein, a facile and straightforward emulsion assisted self-assembly approach has been developed to immobilize a Brønsted basic hexaniobate cluster on the Lewis acidic zirconia. The obtained [C₁₆H₃₃N(CH₃)₃]₆KHNb₆O₁₉/ZrO₂ (C₁₆N-Nb₆/ZrO₂) exhibits a remarkable catalytic activity for the hydrolysis of a Sarin simulant (DMNP): 100% of DMNP was converted under ambient conditions without using basic additives. Based on the control experiments and spectroscopic analyses, a possible reaction mechanism was proposed, suggesting that such excellent catalytic performance of C₁₆N-Nb₆/ZrO₂ is attributed to the synergistic effect between molecular level accessible Lewis acidic ZrO₂ (activating substrate molecules) and Brønsted basic hexaniobates (activating water molecules). As a broad-spectrum catalyst, C₁₆N-Nb₆/ZrO₂ also shows satisfactory performance for the oxidative decontamination of a sulfur mustard simulant.